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isriam

Well-known member
Jan 15, 2015
201
PHX
Looking for some guidance on some simple questions.

Pool: 13k, plaster, 4 feet deep play pool with attached spa.
Equipment: Jandy Aqualink system with Pentair 60sqft DE, Pentair Intelliflow, 399btu gas heater, 1/2hp booster pump for polaris 280.
Location: Dallas Tx

FC:7
CC: .5
TA: 70
PH: 7.2
CH: 500
CYA: 120+

Unfortunately, I've been using trichlor pucks for the past year constantly with 2-3 in the in line chlorine box. I've never had issues and Sunday I found green algae on the side of the spa and parts of the pool. I went to the pool store and he said my water CYA was so high I needed to drain my pool. Well I'm a DIY so after spending hours and hours here, I've picked up 6 gallons of bleach and plan to do the BBB method for awhile.

I've drained about 20% of the pool so far and refilled it over the past 2 days. I pumped 2 gallons of bleach in so far just to keep the FC levels high enough.

I have a couple questions about this process. First, does the variable speed pump affect the amount of time its suggested to run before you measure/check things? And second, does it ever get easier than adding bleach every day? Keep in mind I'm coming from 5 years of various pool ownership where I simply loaded up trichlor pucks and let them sit all summer/winter with no issues until now.
 
Well, I can tell you that your pool needs attention almost everyday, even if it's just a few cups of bleach. But sometimes that's all it takes to keep the algae away. Unfortunately your CYA got away from you and the pool store didn't help matters. So here's a basic road map:
1 - Stay away from pool store, testing and products!
2 - Remove and/all pucks/tablets, and do not use their "bags of shock"; put noting else in your pool other than liquid bleach at this time
3 - Order the proper test kit ASAP (TF-100 link below) and do your own testing - it's easy!
4 - We need to know what your current CYA level is, and that is not possible unless you get one of the recommended test kits.

Please review the Pool School, SLAM, and Chlorine/CYA links below. That's where we're heading. :)
 
I don't think pump speed affects things much for test purposes. You just want it all to mix thoroughly. If you're in a hurry, break out the brush and set up some cross currents.

I go out back several times a day to smoke, so it's no chore for me to dump a quarter of a jug in every day. If it bugs you, look at stenner pumps or peristaltic pumps or the liquidator to automate bleach injection, or convert to a saltwater pool and use a generator to create bleach right in the return line.

There's a whole subforum dedicated to that stuff: Chemical Automation and The Liquidator be sure to toggle the options way at the bottom so you see threads going back more than two weeks.
 
I have the TF100, purchased it yesterday and got it today. I'm on a good start. I tested CYA today and it read 120+ and FC was 7 so I'm still really high. I guess now its just a slow process, keep my FC high until my CYA drops as i drain what I can from the pool and refill?
 
isriam said:
I have the TF100, purchased it yesterday and got it today. I'm on a good start. I tested CYA today and it read 120+ and FC was 7 so I'm still really high. I guess now its just a slow process, keep my FC high until my CYA drops as i drain what I can from the pool and refill?
Click to expand...
Yep. It can be done. Maintain appropriate FC for the CYA level and it works. I got out of the clutches of the pool stores and the pool service guy with CYA of about 240 and water restrictions in place. I will tell you from experience, it's a lot easier maintaining the pool with CYA near 50 than with 200+
 
Drained and got my cya down to 60. Performed the slam yesterday and oclt last night. I'm confused by the results. I had 36 fc and .5 cc at dusk and at dawn 32 fc and .5 cc. How am I losing chlorine if I have no cc?
 
Please add your state to your location in your profile.

Welcome to TFP!

You are losing chlorine because it is killing algae. You did not test CC because of timing. SLAM is not a one day thing.
 
Remember .... The key to SLAM is “Maintain” until 3 objectives are met:
1. Water is clear
2. You do not lose any more than 1ppm of FC overnight (that's the OCLT)
3. CC (Combined Chlorine) is <.5
** You MUST meet ALL 3 items above to properly do a SLAM. Simply “spiking" the FC higher than normal isn't SLAMming, therefore there’s a good chance your algae will return.

SLAM may take just a few days or even a week or two! That is absolutely critical for success.

At the same time, continue to run your pump 24/7. Remove any “muck” and debris, scrub all parts of your pool to expose any algae, and vacuum/clean (or backwash) filter as necessary. You may have to do this several times. It's a lot of babysitting, but with patience and consistency, you will succeed.
 

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When you say you don't see it, do you mean you're getting a test reading of zero? Just to clarify ... having no combined chlorine is of course very good. But just because it's zero doesn't mean you won't lose Free Chlorine during the day. FC will disappear on any given day just by doing its job to sanitize the water and loss from the sun. So you're not imaging things. FC will still drop even when CC is already at zero. :)
 
Sounds like you need to go search for some posts about CC by chemgeek in The Deep End... . There are threads there that will tell you everything you could possibly want to know about CC.

Only he can explain the deep dive chemistry behind what you are asking. We just say number low, good. Number high, bad. LOL
 
I've read a few, but really I just thought it was instant right, OCLT you see FC go down, and CC go up because there is no sun to eat it. What I saw was FC go down, and CC never rise above .5. Either I'm testing wrong, or the CC is delayed in showing in the test? I'm just kinda confused by that.
 
CC is Combined Chlorine so is a chemical that has chlorine attached to it but is not as strong an oxidizer as hypochlorous acid (HOCl) that would react with DPD dye to register as FC nor any chemical that converts to HOCl quickly such as hypochlorite ion or chlorine attached to Cyanuric Acid (CYA). Typical examples of CC include inorganic chloramines (monochloramine, dichloramine, nitrogen trichloride -- though monochloramine usually dominates) and organic chloramines such as chlorourea, chlorocreatinine, chlorine attached to nitrogenous amino acid units in proteins (lysine, asparagine, glutamine) and to most isolated amino acids directly.

The reason you can see a chlorine demand and not see much CC is that these chlorinated intermediate chemicals get further oxidized by chlorine so that chlorine is no longer bound to the resulting end products. So you can think of CC is representing an intermediate chemical on its way to further oxidation. So you would only see CC with large enough amounts of chemicals that combine reasonably fast with chlorine but are slower to get further oxidized OR with chemicals that are slow to react with chlorine and build up to higher concentrations in the water (so eventually their chlorinated intermediate concentrations are proportionately higher as well). Urea is the latter case where it can build up over time because it is slow to get oxidized by chlorine. This most typically happens in indoor pools which is one reason why they show more CC. The UV in sunlight in outdoor pools breaks down some chlorine into very powerful but short-lived oxidizers called hydroxyl radicals and these can oxidize urea and other organic precursors before they get a chance to react with chlorine. The UV in sunlight also breaks down dichloramine directly.

Precursor + Chlorine ---> CC
CC + Chlorine ---> End Products

If the step from CC to End Products is fast, then you won't measure the intermediate CC because it is too short-lived, but you'll still see a chlorine demand since chlorine is used/consumed in each of the two steps. Algae has a large number of organic chemicals, but most of these that react with chlorine to form intermediates also continue to react with chlorine to form end products. Also, much of the CC that is formed is kept inside the now dead cells that get caught in the filter so would not show up in tests of the bulk water. This would be most especially true of the larger molecules such as proteins and DNA and various membranes.
 
**** a reply from the master! So what you're saying is the chlorine is killing things but maybe pee from the kids and not algae? If not it's cool I think the gist is keep a slam going until oclt shows accurate. :)
 
Not exactly. The chlorine may be killing algae as well or instead (algae is made up of chemicals -- they're just biological). The point is that you can't expect to see CC. While the presence of CC usually means something is going on that needs attention, the absence doesn't mean there isn't a problem or that there can't be any higher-than-normal chlorine demand. You've got the gist which is that you hold the SLAM until you pass the OCLT. We also say to hold it if you've got significant CC or the water is not clear, but there are some exceptions in some cases.
 
It looks like iron to me. If it is, the ascorbic acid will fade it pretty quickly. Then you'll have choices for how to remove the iron from the water -- sequester it, dilute to remove it, Metal Magic or CuLator to try and remove it, or advanced methods using sodium carbonate (pH Up) in the skimmer to try and precipitate metal onto the filter to backwash/clean.
 

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